 |
 |
 |
|
||||||
|
|
|||||||
|
||||||||
|
||||||||
|
Mapping Benthic Habitat Around Oil Platforms in the Santa Barbara Channel, California
U.S. Geological Survey (USGS) scientists Pete Dartnell and Guy Cochrane conducted multibeam mapping in the eastern Santa Barbara Channel from August 5 to 15 aboard the research vessel Maurice Ewing. The survey was funded by the Minerals Management Service, whose staff are interested in maps of hardbottom habitats, particularly natural outcrops, that support reef communities in areas affected by oil and gas activity. The maps are also useful to biologists studying fish that use the platforms and the sea floor beneath them as habitat. The main survey area is adjacent to an area previously mapped with a multibeam-sonar system by the Monterey Bay Aquarium Research Institute (MBARI; see the MBARI Santa Barbara Basin Multibeam Survey Web page) and extends eastward a sufficient distance to encompass oil platforms in the region. Data from this part of the survey, which includes Platforms Habitat, Grace, Gilda, Gail, and Gina, will be used to delineate and characterize benthic habitats and geology for improved management of fisheries and other natural resources. Good weather and the absence of operational problems allowed mapping of two additional areas: (1) part of the submarine canyons along the continental slope south of Port Hueneme; and (2) the Footprint area south of Anacapa Island, which has been studied extensively by rockfish biologists and is considered a good site for a marine protected area.
Mapping of the sea floor was continuous, and the technology permitted mapping beneath the platforms, where hardbottom has been created through the biologic activity associated with the platform structure. Invertebrates, mainly mussels, attach to the tops of platforms and eventually fall to the sea floor, where their shells accumulate in mounds below the platforms. The recently collected mapping data, now being interpreted, will provide more information about these mounds and about the natural seabed in this part of the Santa Barbara Channel, which is likely dominated by sedimentary deposits surrounding rare rocky outcrops. Of interest to the Minerals Management Service are the locations and relief of hardbottom features that support reef communities in areas that could be affected by oil and gas operations, such as anchoring and pipeline replacement. Proposals by two companies to place liquefied-natural-gas (LNG) facilities in this area, including a proposal to use Platform Grace as a docking site for ships, have led to a USGS report about potential geologic and seismic hazards. Additional information is available in the Sound Waves article "Report on Hazards Offshore California's Ventura County Coast Compiled in Response to Congressional Request," this issue; and USGS Open-File Report 2004-1286.
|
 |
in this issue:
Coastal Ground Water Discharge Benthic Habitats Near Oil Platforms
Suspended Sediment, Turbidity, and Fish Feeding Behavior USGS Monterey Bay Science Prototype
USGS Biologists Receive DOI Honor Awards
Netherlands Students Assist USGS in Florida
USGS Contributes to New Book About Point Loma |
||||||||||||||||||||||||
U. S. Department of the Interior | U.S. Geological Survey
previous story
cover story:
